As the booster thrust is somewhat greater than the gross lift-off weight, I think the thrust will win.

the 5-seg.SRB's 3.5 Mlbs. is the PEAK thrust that is available a few seconds after lift-off and for about 15 seconds, then, the SRB thrust falls, falls, falls, falls to half and less within the 123 seconds of the SRB burning (see the graph below about the shuttle-SRB thrust curve) so, the SRB "peak" thrust is a good figure to do a comparison, but NOT to know how much tons the new SRB can lift to 55+ km. of altitude

that's why the early CLV upperstages' mass (calculated by NASA engineers!) was ONLY 182 mT MAX and NOT "250", "300" mT or more (as the 3.3 Mlbs. peak thrust of the standard SRB could suggest...)

a solid propellent motor can't give a constant thrust (to lift more upperstages' mass) because it's thrust figure/curve depends ONLY from the propellent's internal shape (that, in a shuttle-SRB is an 11-points' star)

infact, each shuttle-SRB can lift itself and ONLY 240 mT of (shuttle, ET, payload) mass to 45 km. of altitude

do you know why the Shuttle flys?

it flys thanks to its three SSME that can "throttle" between 67% and "109%" ...these engines starts at 104% the power at lift-off then "throttle down" in the first seconds after lift-off to compensate the high SRB thrust and to keep the acceleration to 3G max, so, when the SRB thrust falls, they "throttle up" again to lift the Shuttle to LEO, that, also, thanks to the SSME vacuum thrust that reaches over 512 klbf. (while the sea level thrust is only 408 klbf)

if you start from the REAL figures of the max upperstages' mass of both (4-seg. and 5-seg.) motors (that NASA give in its OFFICIAL documents) you'll discover that a 5-segments SRB can't lift (both) 192 mT of upperstages' mass AND the 5th segment's "extra-mass" to 55+ km. of altitude

that since the Ares-1 has no "throttleable" SSME in the 1st stage... about this point, I doubt the astronauts can survive the lift-off since the (uncontrollable) SRB thrust in the 10-15 seconds after lift-off could give a LAS-like 10G+ acceleration...

the 5-seg.SRB's 3.5 Mlbs. is the PEAK thrust that is available a few seconds after lift-off and for about 15 seconds, then, the SRB thrust falls, falls, falls, falls to half and less within the 123 seconds of the SRB burning

Naturally! As the gigantic mass of propellant gets used up, the booster gets lighter and lighter. If they didn't design it to reduce the thrust at the same rate as the mass decreased, then the G load would increase throughout the powered flight. That is not a bad thing for efficiency, but they wanted a gentle 3G all the way ride, so they designed the SRB to burn that way. By the way, also notice the dip in thrust at about 1 minute and then it goes up again. This coincides with the max Q portion of the flight, where they want to be gentler as they punch through the atmosphere. You can rely on NASA to have designed this thrust curve very carefully to get exactly the ideal thrust at every second of the burn.

Remember, NASA is full of rocket scientists, and assuming you know more than they do about rockets is really a dumb thing to do.

I'm always very serious in all my articles, opinions, posts and comments

You may want to work on both your content and its presentation if you want to be taken seriously. Everything I've seen from you looks very much like trolling. People don't react kindly to trolling.

LITERALLY "everytime" I talk, write, post (everywhere) about TOO "disliked" arguments like this, I receive lots of insults and accuse of "spam" and "trolling" ... ... but it's very hard to say that against me since I always give data, evaluations and calculations that confirm (or could confirm) my claims... like the detailed 5-segments SRB data below:

Naturally! As the gigantic mass of propellant gets used up, the booster gets lighter and lighter. If they didn't design it to reduce the thrust at the same rate as the mass decreased, then the G load would increase throughout the powered flight. That is not a bad thing for efficiency, but they wanted a gentle 3G all the way ride, so they designed the SRB to burn that way. By the way, also notice the dip in thrust at about 1 minute and then it goes up again. This coincides with the max Q portion of the flight, where they want to be gentler as they punch through the atmosphere. You can rely on NASA to have designed this thrust curve very carefully to get exactly the ideal thrust at every second of the burn.Remember, NASA is full of rocket scientists, and assuming you know more than they do about rockets is really a dumb thing to do.

look at the SRB thrust curve... the thrust falls quickly while the SRB dry mass remains high... good luck...

about the "gentle thrust"... if could be SO HIGH in the first 10-20 seconds after lift-off to be similar to a LAS-like 10G+ acceleration, the astronauts can't survive to...

after all, the standard SRB was NEVER launched ALONE to know the REAL acceleration at 3.3 Mlbs. of thrust...

SRB dry mass is quite small; it is not high at all! Only 229,739 pounds. (By the way, all numbers listed are weight and not mass. Divide pounds by 32 to get mass in units of slugs.) Anyway, it is the total mass, including the upper stage, payload, and all propellant remaining in the vehicle, not the dry mass of the SRB, which in combination with thrust determines acceleration at each moment. As propellant is used up and the total weight goes down they want to lower the thrust to keep the acceleration in just the right range. Total weight at each second is NOT graphed in your attached picture, but you can calculate the total weight at launch and at the moment the SRB burns out from the information in the text next to the graph. The 5 segment SRB maximum thrust is listed as 3,467,300 pounds and the graph shows that the initial thrust is about the maximum. The initial thrust to weight ratio is listed as 1.4, so the total weight of the vehicle starts out as the thrust divided by 1.4, or 2,476,642 pounds. This means initial acceleration is 1.4 G. The chart also lists the 5 segment SRB propellant weight as 1,424,070 pounds. Subtracting that from the total launch weight tells you that at the moment the SRB runs out of propellant the total weight of the whole vehicle is 1,052,572 pounds. This includes the weight of the fully fueled second stage and the payload as well as the empty weight of the 5 segment SRB. At 125 seconds after launch, the graph shows thrust to be about 2,000,000 pounds, so the vehicle has enough thrust at that time for about 2 G acceleration even though the thrust is now less than the liftoff weight. That sudden drop in thrust at 130 seconds is just the booster shutting down in preparation for staging. A similar calculation could be done for the RSRB; Iâ€™ll leave that to you.

SRB dry mass is quite small; it is not high at all! Only 229,739 pounds. (By the way, all numbers listed are weight and not mass. Divide pounds by 32 to get mass in units of slugs.) Anyway, it is the total mass, including the upper stage, payload, and all propellant remaining in the vehicle, not the dry mass of the SRB, which in combination with thrust determines acceleration at each moment. As propellant is used up and the total weight goes down they want to lower the thrust to keep the acceleration in just the right range. Total weight at each second is NOT graphed in your attached picture, but you can calculate the total weight at launch and at the moment the SRB burns out from the information in the text next to the graph. The 5 segment SRB maximum thrust is listed as 3,467,300 pounds and the graph shows that the initial thrust is about the maximum. The initial thrust to weight ratio is listed as 1.4, so the total weight of the vehicle starts out as the thrust divided by 1.4, or 2,476,642 pounds. This means initial acceleration is 1.4 G. The chart also lists the 5 segment SRB propellant weight as 1,424,070 pounds. Subtracting that from the total launch weight tells you that at the moment the SRB runs out of propellant the total weight of the whole vehicle is 1,052,572 pounds. This includes the weight of the fully fueled second stage and the payload as well as the empty weight of the 5 segment SRB. At 125 seconds after launch, the graph shows thrust to be about 2,000,000 pounds, so the vehicle has enough thrust at that time for about 2 G acceleration even though the thrust is now less than the liftoff weight. That sudden drop in thrust at 130 seconds is just the booster shutting down in preparation for staging. A similar calculation could be done for the RSRB; Iâ€™ll leave that to you.

all the optimists and the 5-seg.SRB fans always do the same mistake dazzled by the amazing peak thrust of the new booster, so, they do some calculations based on this big figure without see the small things

well, I try to explain my point with an example:

just imagine that you have an airplane with two jet engines able to fly 200 mT of its own structure, passengers, fuel, etc.

if you want to DOUBLE the weight of the plane (structure, passengers, fuel, etc.) you MUST double also the POWER of the jet engines, so, you MUST adopt FOUR jet engines with the same power of the first airplane OR two engines with TWICE the power of the old engines

if you DOUBLE the weight but increase the jet power of a mere 50% (three engines) the airplane never takes off or crashes

now, just imagine the 5-seg.SRB as a new airplane... its weight is a PERFECT +25% of the old SRB... 731.5 mT vs. 586 mT of the 4-seg. version (without the Nose Cap) ...but its thrust is NOT a +25% the old SRB, so, it's like a new airplane with 100% more weight and only 50% more power

I've already remarked this point 15 months ago in my 5-seg.SRB article, but many forums' users have said me that it was not the REAL figures of the REAL 5-seg.SRB... ok!

unfortunately, the latest specs from NASA (in my first post) confirm a +25% "extra-mass" with only +7% of extra thrust, so, in one or more points of its flight profile, the new SRB will have too much weight for the given thrust

Clear words..that's just bullshit..first of all your numbers are old..you had that discussion already on other forums and you were pointed there on some things you have to consider.

Second: You assume that the 4 segment booster wouldn't have any reserves for this task. When you take your planes..not a single plane would be capable of stretching then.

Third: Just use rocket equations and calculate the stuff. Write a program to simulate the whole launch if you feel better then or pay me and I run one for you

The only thing that was basically under discussion the last year or so was if the Ares I can launch the then still overweighted Orion into the proper orbit. As this was (and we are still until spring next year) in the design phase, it wasn't a problem because payload masses were still changing. That's what a design phase is for.

_________________"The hardest hurdle to space isn't the technicalities and money. But rather, the courage and the will to do it." - Burt Rutan.

That is a bad analogy. Double the weight of the wings but the same weight of the fuselage, for a 50% increase of the total airplane is a better analogy.

It is not ONLY the weight increase of the SRB that counts. It is the weight increase of THE ENTIRE VEHICLE that counts. Your own web page says the weight of the whole vehicle went up from 1,693,695 pounds to 2,036,356 pounds. That is a 20% increase, not 25%. Because even though the SRB weight increased by 25% but the rest of the vehicle did not.

gaetanomarano wrote:

...unfortunately, the latest specs from NASA (in my first post) confirm a +25% "extra-mass" with only +7% of extra thrust, ....

They do not! Your own web page says the weight of the whole vehicle went up 20%. And it also says the thrust to weight ratio went down from 1.74 to 1.57. So yes, the new 5 segment lifts off at a lower acceleration (1.57 G instead of 1.74 G) but it STILL LIFTS OFF! From the GLOW and T/W I calculate the initial thrust went up by 8.5% not 7%. And since the engine has 25% more propellant producing only 8.5% more thrust, it will BURN LONGER. So, just as those NASA people said, that 5 segment vehicle with the numbers they published will do what they said it will, which is place the Orion in orbit. They are not stupid enough to publish numbers that do not add up.

As the booster thrust is somewhat greater than the gross lift-off weight, I think the thrust will win.

...snip...

do you know why the Shuttle flys?

...snip...

The shuttle leaves the launch pad because the thrust exceeds the weight. This is also true for Ares I, so that too will leave the pad. Your assertion that it cannot leave the pad is therefore false. You have delusions of competence. Any normal person in your situation would just ask about an apparent inconsistency, not keep insisting that they know better.